Manufacturing of papermakers' fabrics traditionally include a number of different types of machines and equipment. For instance, manufacturing plants generally include a weaving loom for weaving of the base fabrics which, for example, may comprise woven monofilament mesh fabrics, a finishing machine onto which the base fabric produced on the weaving loom is placed for heat treating or setting of the woven base fabric in order, for example, to fix the size of the fabric, and a needle loom for needling fibrous material to the base fabric to fully integrate and unite the fibrous material into and amongst the base fabric and themselves.
In addition, these plants also generally include a batt-making line for producing a carded fiber web or batt of narrow width, and a cross lapping apparatus for producing a cross-layered fibrous web of a width corresponding to the width of the base fabric. The cross-layered fibrous web may be applied directly from the cross lapping apparatus to the base fabric, or may first be tacked together, rolled onto a separate roll and then later unwound for being applied to the base fabric. The batt-making line may, in turn, include equipment for opening of textile fibers, equipment for blending of the fibers, and equipment for carding or orienting of the fibers to produce the carded fiber web or batt.
Needle looms are complicated, sophisticated pieces of equipment which generally have a plurality of separate needling stations or zones, each of which generally includes a plurality of juxtaposed needle boards mounted to a machine frame so as to extend across the working width of the loom. The needle boards each include a multiplicity of needles arranged in rows and columns which are moved up and down to pierce the fiber layer applied to the endless base fabric in order to lock the fibers to the base fabric. Generally, several passes are made past the needling stations in order to fully and properly needle the fibrous layer to the base fabric. Further, when needling cross-layed fibrous webs to the base fabric, the full-width needle boards are initially operated so as to tack the cross-layed web in place in order to initially hold the layed fibrous material in place. The tacking operation is generally accomplished at a slow stroke rate, but at a high fabric advance rate per loom stroke.
After the fibrous material has been tacked in place, the needle boards are then operated utilizing the needles at full penetration to fully lock and unite the fibrous material to the base fabric. This is accomplished at a faster speed than that at which the fibers are initially tacked in place, and thus, the needle loom has a greater throughput. After complete and full needling, the endless fabric web having the fiber layer needled thereon is taken off and may be placed on a finishing machine for heat-setting of the finished felts and/or for other surface treatments, such as compaction, washing and/or vacuuming.
In terms of the operational process in the manufacture of endless papermakers' felts, the piece of equipment generally having the most downtime, and also, the most expensive piece of equipment, is generally the needle loom. In terms of the speed of operation, in present day plants, only one finishing machine is required for every two to three needle looms. That is, one finishing machine in a plant can supply finished, heat set base fabrics for two to three needle looms operating at conventional speeds and/or can finish or surface condition produced felts from two to three needling looms. Simply put, conventional needling looms are among the most expensive pieces of machinery in a papermakers, felt production plant, and also, among the slowest operating by virtue of having a substantial amount of downtime. Downtime results from a number of factors, for example, set up time for the fabric and needle boards, needle board repair and replacement, etc. As a result, the run or operating time of the needling loom is often small compared to the downtime. For example, it has been determined that in certain applications the needle loom downtime has resulted in loom utilization of only about fifteen percent of the total number of hours available. Consequently, it is most important in order to efficiently and economically produce endless needled fabric to minimize needling loom downtime and to maintain the needling looms operating at full capacity and performing their intended needling functions at all times, i.e., increasing overall availability of the needling loom.
During operation of the needle loom, the needles of the needle board are initially subjected to natural wear, as well as a more or less large amount of needle breakage. As a consequence, an increasingly larger number of needles are no longer available for the needling process. Needles which fail during operation of the needle loom increasingly deteriorate the quality of the produced needled fabric. Damage to the needles reduces the usability of the needle board earlier than the time set at which, due to general wear, all needles would be replaced or a replacement of the entire needle board and the attached needles. In addition, it is known to periodically replace a percentage of the needles, typically the oldest needles, even though they are not broken. For example, maintenance of the needle boards might include replacement of one or more rows of needles every three to four days of needle loom operation. Accordingly, a needle board at any one time will contain needles of varying age and wear.
The needle boards are arranged in the needle loom in one or more zones overlying and/or underlying the endless fabric web to be needled. A typical needle loom, such as a duplex loom in which needling of the endless fabric web occurs concurrently from both above and below the web being processed, may include four zones of needle boards. Each zone may include, for example, eight to ten needle boards (each needle board having seventeen rows of needles) which ultimately require replacement when the needles become worn and/or damaged during operation of the needle loom.
The needle boards have previously been replaced by manual operation. In this regard, an operator after stopping operation of the needle loom, would withdraw a needle board from a needle board zone one board at a time. The withdrawn needle boards would be manually transported from the needle loom to a storage cart. Once all of the needle boards for a given zone were removed, the replacement needle boards would be inserted into the needle loom, one needle board at a time. This replacement process would require that an operator be constantly manually transporting worn or damaged needle boards withdrawn from the needle loom and replacement needle boards back and forth between one or more designated storage carts. Due to the large number of needle boards, the replacement process could take anywhere from six to eight hours per needle loom zone. As previously noted, it is most important in order to efficiently and economically produce endless needled fabric webs that the needle looms be operating continuously at full capacity at all times. Thus, the extended down time of the needle loom for needle board replacement has been recognized as a serious drawback in the efficient and economical production of needled fabric webs.
Accordingly, there is an unsolved need for an apparatus and method to enable the removal and replacement of needle boards in a needle loom with a minimum amount of needle loom down time and operator intervention so as to maintain the efficient and economical operation thereof in the production of endless needled fabric webs.